The basic design and operation of the standard bicycle has changed very little since its inception, still being operational to pedal power applied by the operator rotating a crank to a shaft having a fairly large sproket and chain connected to a smaller sprocket fixed to the rear axle for driving the rear wheel. Improvements to this adaptation have been made over the years with the addition of multiple sprockets of variable diameter fixed to the axle of the rear wheel that can provide a variable speed to the bicycle when the rider manually manipulates a derailer in shifting the chain from one sprocket to the other, depending upon the desired gear ratio.
Although multiple gear ratios are available, including specialized mountain climbing bikes having gear ratios of at least seventeen different speeds (some even greater) for traveling up steep inclines, the disadvantage is a matter of physical endurance and stamina of the rider, because according to published scientific statistics the average person can provide about only one tenth of a horsepower output, and it can be somewhat greater only for a short period of time. Therefore there is a physical limitation as to the speed and hill climbing ability of the bicycle and rider, regardless of how many gears are made available.
The trend with bicycles of today is of lighter structure by the use of very light weight materials as aluminum and other applications such as tires being thinner and the wheels of greater diameter in order to give greater speed and reduce friction and drag with less energy outut. Most bicycles are fairly adequately designed so that a controllable speed on level terrain and downgrade can be provided by the rider without power assistance from another source, as with an auxiliary power device. However, mountainous and hilly terrain and the physical makeup of the rider can present an obstacle for those persons of operating the standard bicycle that is available on the market today, as even experienced riders often have to dismount and push the vehicle to the top of a hill when the incline is too steep.
There is a need for a bicycle having the capability for carrying a payload other than the rider over long distance and terrain that could exceed the rider's endurance and stamina and that still could be operated without need for audiliary power, such as an electric motor or gasoline engine.
A bicycle having a manual auxiliary power system must be compact, lightweight, inexpensive, easy to maintain and completely safe in its application, and it should provide practically anyone, regardless of their physical makeup, endurance and stamina, the capability to maneuver a bicycle in almost any type of terrain without putting an undue physical strain upon the rider.
Prior art discloses several inventions that show considerable improvement in the method for providing auxiliary power to a bicycle, including the application of compressed air, hydraulics and a flywheel for storing energy. However, nowhere in prior art is there disclosed a method for providing a reserve energy source that can be made available to the rider when the requirement for the expenditure of energy exceeds that available and the physical force of the rider has reached its maximum output.
One great difficulty experienced with either compressed air or the application of hydraulics for driving a bicycle when manual pedal power is provided by the rider is the slow rotation of the crank and shaft to the pump, particularly at slow speeds and on an incline where auxiliary power is greatly needed, in that the pump will not provide enough pressure and volume of working fluid to compensate for the greater force that is needed for driving the wheels. The slow pedal movement on startup and on inclines can practically eliminate any benefit gained by having auxiliary power equipment for assisting the rider in moving the vehicle, for the rider still has limited power available for driving the wheels when it is most needed.